Device for recessing blasting cartridges for insertion of detonators and of detonator-retaining clips



2 Sheets-Skeet].

ROLFES Filed Oct. 26, 1943 ING A BLASTING CARTRIDGE FOR I NSER-TION OF A DETONATOR AND OF A DETONATOR-RETAINING CLIP DEVICE FOR RECESS April 23, 1946.

2,398,857 NG A BLASTING CARTRIDGE FOR INSERTION OF A DETONATOR AND OF A DETONATUR-RETAINING CLIP F. H. ROLFES Filed Oct. 2e, 1945 April 23, 1946.

- DEVICE FOR RECESSI 2 Sheets -Sheet 2 III-Z FIG. 13

Patented Apr. 23, 1946 UNIT!) S T ES DEVICE FOR RECESSING BLASTIN'G CAR- TRIDGES FOR INSERTION OF DETONA- 'EORS AND CLIPS F DETONATOR-RETAININ G Fritz Hermann Rolfes, Johannesburg, Transvaal, Union of South Africa Application Gctober 26, 1943, Serial Na. 507,710 In the Union of South Africa December 28, L942 Claims.

This invention relates to devices for recessing a blasting cartridge for the insertion therein of a detcnator and of a clip. for retaining or locking the detonator in its inserted position, and refers, on the one hand, to devices of this type which comprise a tube or other guide means adapted to be fitted over or on to the end of the cartridge and a piercing member which projects towards the mouth of the guide means and is adapted to pierce a lengthwise hole in the cartridge for the detonator, and is concerned, on the other hand, with retaining clips of the kind adapted to be inserted (or part of which is adapted to be inerted) transversely into the cartridge so as to furnish above the end of the detonator or an equivalent projecting part, a locking abutment.

The object of the present invention is to provide an improved device of the type stated whereby a recess in the side of the cartridge for a retaining clip of the kind referred to can be made quickly and easily, and also with accuracy and safety.

According to the invention, our improved device has the tube or guide means thereof provided with a, slot or opening at the side thereof, and has a knife or recessing member which is retractible in or from the said slot or opening in order to permit piercing of the cartridge with the lengthwise hole for the detonator, and is insertible through or into the said slot or opening in order to recess the cartridge transversely for the retaining clip.

More especially, my device comprises a knife or recessing member which is movable inwardly and outwardly with respect to the side of the cartridge into which the piercing member is longitudinally pushed, and which is normally held or retracted clear of the said side but is insertible therein at will, in order to recess the cartridge for the retaining clip.

The transversely movable knife or recessing member may be under constraint to its retracted or clear position by virtue of a spring.

The knife or recessing member may be of bifurcated shape at its cutting or forward end.

Three devices embodying my invention will now be described, by way of example, with referenc to. the accompanying drawings, in which- Fig. l is a view in elevation of one device according to the invention.

Fig. 2 is an elevation of the said device, viewed at right angles to the elevation shown in Fig. 1.

Fig. 3 is a sectional plan view taken in the plane of the line 3--3. (Fig. 1.)

Fig. 4 is. a sectional plan taken in the plane of the line 4P4. (Fig. 2.)

Fig. 5 is a view in elevation of another device according to the invention.

Fig. 6 is an elevation of the said device looking at right angles to the elevation shown in Fig. 5.

Fig. 7 is a sectional plan taken in the plane of the line l-I. (Fig. 5.)

Fig. 8 is a sectional plan taken in the plane of the line ,8--8. (Fig. 6.)

Fig. 9 is a view in elevation partly sectioned of a third device according to the invention.

Fig. 10 is an elevation of the said device looking at right angles to the view shown in Fig. 9.

Fig. 11 is a sectional plan taken in the plane of the line I II l (Fig. 9.)

i 12 is ,a sectional plan taken in the plane of the line I2- I2. (Fig. 10.)

Fig. 13 is a modified form of the knives shown in the other figures and Fig. 14 is another modified form of the knives shown in the other figures.

Referring to Figs. 1-4:

The device comprises a piercer I and guide tube 2, secured to a handle 3. As will be seen from Fig. 3 the piercer I is mounted eccentrically with respect to the guide tube 2, and the interior of the tube 2 is formed with ribs, 4.

A bifurcated recessing knife 5 is rigidly secured to a, substantially rectangular frame 6 which is slidable transversely to the tube 2 in brackets l which are brazed or otherwise secured to the outside of the tube 2. A slot 8 is formed in the tube 2 opposite the bifurcated knife 5, the size of the slot being such as to permit the knife to pass inwardly through the same into the interior of the tube 2, when the frame. 6 is slid transversely in the brackets 1.

As'will be-seen from Figs. 3 and 4, the bifurcated ends 9 of the knife 5 arebevelled or flared outwardly from each other.

These ends 9 are symmetrical with respect to the medial line of the knife 5 and frame 6, which medial line is; in turn, coincident with the centre line of the tube 2 which is co-planar with the aXis of the piercer I.

The device described is operated as follows:

When the device is to be used, the frame 6 is slid transversely in the brackets I so as to retract the recessing knife 5 from the interior of the guide tube 2 (see the position illustrated in Figs. 1 and 3). With the knife in this position, the guide tube 2 is now pushed down over the end of the blasting cartridge to be pierced and recessed. The piercer I is thereby caused to pierce a lengthwise hole downwardly from the end of the cartridge, this hole. being located nearer to the side of the cartridge adjacent to the knife 5. than to the other side (see the relative positions of the piercer I and knife 5 as shown in Fig; 3). Whenthe tube 2 and piercer I have been fully pushed down on the cartridge, the frame 6 is pressed sidewardly so as to force the bifurcated ends 9 of the knife 5 through the slot 8 in the tube 2', so that these ends penetrate through the paper wrapping of the cartridge and through the material of the cartridge itself, unti1 the knife 5 has reached its final inward position as illustrated in Fig. 4. The bifurcated ends 9 of the knife 5 produce in the cartridge two parallel recesses which lie transversely to the axis of the cartridge and eachof which is of a size to permit the firm insertion of the prongs of the retaining clip or staple to be used to retain the detonator eventually inserted in the lengthwise hole of the cartridge. Thereafter the frame 6 is slid in the opposite direction so as to retract the knife 5 from the cartridge and the interior of the tube 2, which is then withdrawn along with the piercer I from the end of the cartridge.

As will be appreciated, with the lengthwise hole and transverse recesses produced in the cartridge by our device, it is reliably assured that the retaining clip or staple will be inserted in a symmetrical position with respect to the detonator inserted into the hole. As usual, the width between the prongs of the staple or clip is such that these prongs pass over areduced part (or more usually the fuze) of the detonator but present diametrically opposite abutments to the part or end of the detonator of relatively enlarged or normal width, thus constituting the hold or grip between the detonator and cartridge.

Referring to Figs. 5 to 8, the device'shown in these figures is similar in substance to that shown in Figs. 1 to 4, and similar reference numerals denote similar parts. In the present device, a bifurcated recessing knife I is transversely slidable in a slot I l (Figs. and 8) in the side of the tube 2, and is connected by a pin l2 at its outer end to the slotted bottom end 13 of a leaf spring 14. This leaf spring is fixed at its upper end to the tube 2 by means of a rivet I5, and is prestressed so as to place the recessing knife l0 under a constant constraint towards its outer or retracted position as illustrated in Figs. 5 and '7. A ring or sleeve [6 is vertically slidable on the tube 2. This ring in its uppermost position (see the position shown in full lines in Fig. 5) does not interfere with the leaf spring l4, but when pushed downwards to the dotted position IBa (Fig. 5) it draws the leaf spring I4 against the tube 2 so that the spring lies substantially flush therewith, which is a convenience when the device is not required for use and is being carried on the person or otherwise transported or stored.

The device just described is used in the manner already indicated with reference to the device shown in Figs. 1 to 4, it being unnecessary, however, for the knife ID to be retracted by a manual or positive movement, since the leaf spring 14 causes the knife In to be retracted automatically whenever the knife is released after completion of the recessing operation.

Referring to Figs. 9 to 12:

The device shown in these figures comprises, like the device shown in Figs. 5 to 8, a springself-retracting knife, which in this device (see Figs. 9 and 12) is denoted by the reference numeral IT. A slot I 8 isformed in the side of the guide tube 2 for the passage ofthe knife H, and the outer end of the knife is brazed or otherwise secured to a leaf spring IS. The top and bottom ends of this leaf spring are formed with slots which are engaged by pins 2| fixed to the guide tube 2. Overthe upper and lower parts of the spring I9 leather or other shields 22 may be provided.

The device just referred to, is operated in'the same manner as the device shown in Figs. 5 to 8.

It is distinguished from the latter device, and the device shown in Figs. 1 to 4, in that the bifurcated knife I! is only made sufi'iciently long to pierce through the paper wrapping of the cartridge and penetrate a comparatively small fraction of the distance to which the retaining clip or staple will penetrate for the purpose of securing the detonator or capped fuze. In practice it is the initial penetration of the clip through the paper wrapping of the cartridge which is attended by the greatest resistance, and the relatively short or partial recessing effected by the present device will be found to facilitate satisfactorily the insertion of the clip in most cases.

If desired, in the case of any of the bifurcated knives 5, I0, and IT, or any other similar knife, the root or base of the slot between the bifurcations may be pointed V-shaped or sharpened, as shown at 25, Fig. 13, and the knife'so arranged that such root or base portion penetrates the side of the cartridge as well as bifurcations themselves. This modification is necessary if it is desired that the connected or rear portion of the staple or clip should be pressed right into the side of the cartridge.

While knives of the bifurcated kind have been referred to above, it is to be understood that the recessing knife may be of single-pointed or any other form, as at 26, Fig. 14, suited to the nature of the recess required and the clip to be inserted therein.

I claim:

1. A device for recessing a blasting cartridge for the insertion therein of a detonator and of a clip for retaining the detonator in its inserted position, comprisin a tubular guide adapted to be fitted over the end of the cartridge, a piercing member which projects towards the mouth of said tubular guide and is adapted to pierce a lengthwise hole in the cartridge for the detonator, and a recessing member which is retractible through the side of said tubular guide in order to permit piercing of said hole by said piercing member and is insertible through said guide in order to recess the cartridge transversely for insertion of said clip.

2. A device for recessing a blasting cartridge for the insertion therein of a detonator and of a clip for locking the detonator in its inserted position comprising a tubular guide adapted to be fitted on to the end of the cartridge, a piercing member which projects towards the mouth of said tubular guide and is adapted to pierce a lengthwise hole in the cartridge for the detonator, a knife which is movable inwardly and outwardly with respect to the side of said cartridge'through the side of said tubular guide and which is' normally retracted clear of the side of said cartridge but is insertible therein at will in order to recess the cartridge for the locking clip.

3. A device, as claimed in claim 1, comprising a spring whereby the transverely movable recessing member is under constraint to its retracted position.

4. A device, as claimed in claim 2, wherein said knife is recessed to provide a bifurcated shape at its cutting end.

5. A device, as claimed in claim 1, comprising means for holding the recessing member in its innermost position relative to the tubular guide when the device is not required to be used but is being stored or carried.

FRITZ HERMANN ROI-FES. 

